This is unironically something we should be encouraging. Just because they don’t feel pain and are unthinking killing machines does not make them invincible, in fact it makes them super vulnerable. Are you gonna make their bones out of titanium? gonna give them diamond skin? You’d pretty much have to. People in general are vulnerable, but the response to fear and pain are our two biggest tools to help us learn what is and is not dangerous. People who are genetically immune to pain from those rare diseases don’t usually make it to adulthood because they end up harming themselves and not realizing it’s a life threatening injury.